Definition of polar in English:

polar

Syllabification: po·lar
Pronunciation: /ˈpōlər
 
/

adjective

  • 1Of or relating to the North or South Pole: the polar regions
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    • It warns of adverse consequences such as the melting of glaciers and polar icecaps, leading to rising sea levels.
    • And also things like what's happening to the glaciers and the different mountain regions or the polar ice caps or ocean temperatures.
    • Glaciers, permafrost and polar ice caps are melting, and droughts, floods and more extreme storms are occurring more frequently in many parts of the world.
    Synonyms
    cold, freezing, icy, glacial, chilly, gelid, hypothermic
  • 1.1(Of an animal or plant) living in the north or south polar region.
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    • They were found alongside the remains of mammoth, reindeer and polar fox, and they appear to have been eaten by their human masters.
    • But populations of frogs, butterflies, ocean corals, and polar birds have already gone extinct because of climate change, Parmesan said.
    • But polar species are far fewer in number and may not face the same extinction risk as those that live in more confined hot spots with greater biodiversity.
  • 1.2 Astronomy Of or relating to the poles of a celestial body.
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    • This means that its equatorial radius would be 40 kilometers greater than the polar radius.
    • Scientists will also dig into the puzzling asymmetry in the Sun's magnetism that was discovered by Ulysses during the first polar passes.
    • Also there are areas at higher elevation on the rim of polar craters that see the Sun more than half of the time.
  • 1.3 Astronomy Of or relating to a celestial pole.
  • 1.4 Geometry Of or relating to the poles of a sphere. See pole2.
    More example sentences
    • The Earth is an oblate spheroid, with polar diameter some 45 km less than the equatorial diameter.
  • 1.5 Biology Of or relating to the poles of a cell, organ, or part.
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    • The most utilized fluorescent markers of dead cells are polar DNA-binding dyes, unable to penetrate intact plasma membranes.
    • Class 1 mutations (b and c) elongate cells and cause predominantly polar bud site selection.
    • Angiosperm seeds are comprised of an embryo and endosperm resulting from double fertilization of the egg cell and two polar nuclei, respectively.
  • 2 Physics & Chemistry Having electrical or magnetic polarity.
    More example sentences
    • Another active area of biophysical research concerns the study of the interactions involving charged, polar and polarizable groups of atoms in proteins.
    • For example, HCl comprised of the atom Hydrogen and Chlorine is polar.
    • It is polar, that is the oxygen atom has a negative electrical charge while the two hydrogen atoms are positive.
  • 2.1(Of a liquid, especially a solvent) consisting of molecules with a dipole moment.
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    • With sodium chloride and water, the saturated condition is rapidly reached because the attraction between the sodium chloride ions and the polar water molecules is so strong.
    • In addition, the growth of coatings containing higher levels of solids such as epoxy resins, polyesters and urethanes has increased the demand for polar solvents such as ethyl acetate.
    • Recent work in our laboratory has explored the clustering behaviour of organic polar solvents such as methanol, 6 ethanol and butanol.
  • 2.2(Of a solid) ionic.
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    • The compound lithium hydride, LiH, is a polar covalent solid that reacts with water to liberate hydrogen gas and form basic solutions of the metal hydroxide.
    • The C-Cl bond is polar covalent, Na-Cl is ionic, and the C-C bond is pure covalent with each atom sharing the bonding electrons equally.
    • In addition, the dipolar water molecules are supposed to be strongly bound to ionic and polar parts along the protein surface.
  • 3Directly opposite in character or tendency: depression and its polar opposite, mania
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    • But then again the two characters could never be described as polar opposites.
    • Where the film excels is in comparing and contrasting the two ostensibly polar opposite schemes.
    • Every time it comes to the forefront, you're caught off guard, as it's polar opposite of the main comedic tendencies of the film.
    Synonyms
    opposite, opposed, dichotomous, extreme, contrary, contradictory, antithetical

noun

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  • 1 Geometry The straight line joining the two points at which tangents from a fixed point touch a conic section.
    More example sentences
    • Sturm's theoretical work in mathematical physics involved the study of caustic curves, and poles and polars of conic sections.
    • This exactly means that the directrix is the polar of the focus, while the focus is the pole of the directrix with respect to the parabola.
    • Bobillier is best known for his work on polars of curves and of algebraic surfaces.
  • 2 Astronomy A variable binary star that emits strongly polarized light, one component being a strongly magnetic white dwarf.

Origin

mid 16th century: from medieval Latin polaris 'heavenly', from Latin polus 'end of an axis' (see pole2).

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